Web push notification contains 4 elements: icon, title, body and image.
Our general recommendations for the proper work of push notifications are:
Title: maximum 25 characters
Body (without picture): maximum 100 characters
Body (with picture): maximum 35 characters
Icon: 192x192px
Image: 360x240px
File Type: JPG/PNG, animation is not allowed
The thing is that push notifications have different formats in each browser, OS, screen resolution, etc. We have collected the most common browsers, which are used among Advertisers:
Chrome 75 on Windows
With image:
Title in 1 line: 25 characters
Title in 2 lines: 50 characters (in this case body of the push notification is not shown)
Title more than 50 characters: 3 dots will be shown after 49th symbol (in this case body of the push notification is not shown)
Body: 38 characters
Without image:
Title in 1 line: 25 characters
Title in 2 lines: 50 characters (in this case body of the push notification is cut)
Body: maximum 150 characters, 3 dots will be shown after 149th symbol
Body: maximum 100 characters, if you have title in 2 lines
Please note: the most important for desktop Chrome is title, because it is shown in all of the cases. Icon also shown all the time without influencing on the body and picture.
Firefox 65 on Windows
Image: is not shown
Title is always in 1 line: 44 characters, 3 dots will be shown from the 45th character
Body: maximum 200 characters, 3 dots will be shown from the 201st character
Opera 58 Windows
Title in 1 line: 24 characters
Title in 2 lines: 49 characters(in this case body of the push notification is not shown)
Without image:
Body (if the title is in 1 line): maximum 179 characters (if the title is in 1 line)
Body (if the title is in 2 lines): maximum 107 characters
With image:
Body: maximum 34 characters, 3 dots will be shown from the 35th character
Please note: this recommendations are working for Latin alphabet, all of the other alphabets may have different requirements.